We have to use our brain to calculate something manually like we write with pen/pencils for income tax return in the paper where paper act as a storage which is storing info about my/our income tax
The info contains some procedures which is known as algorithm,instructions or programs which carrying out the calculations,numbers or data.
During the calculation data takes process in the human brain which serve as central processor and the initial,intermediate an final results are included/recorded in the paper.
The brain performs two distinct functions:
1.A control function
Control function actually interprets the instructions and check that the instructions performed perfectly and in the proper sequence.
And an executive function performs the specific steps to performs addtition,multiplication,subtraction and division.
Example: A pocket calculator serves as a aid to the brain